1. Field of the Invention
The present invention relates broadly to marine winches, particularly sailing winches, and is more specifically concerned with a marine winch drum of novel and beneficial conformation.
2. Prior Art
In the field of marine winches, such as those conventionally used to adjust the fabric lines or halyards of sailing craft, the winch broadly comprises a base element mounted at an appropriate locations on the mast deck or surface structure of the craft and journalled thereto, a vertically or horizontally oriented drum which may be manually, electrically or hydraulically operated through a gear train acting upon the drum. In many instances the gear train is of the reduction gear type and comprises a number of output speeds or mechanical advantages which are selected by the user through the agency of a shift mechanism.
One of the problems encountered in winches of the prior art is slippage of the line on the winch drum relative to the wraps of line placed thereon. Thus, purchase of the spool of the drum on the lines has been deficient, thereby often requiring multiple adjacent wraps of the line upon the spool to achieve a given holding power. Thus, not only are multiple wraps of line usually required to be received onto the spool to handle the sailing line load, but also considerable line abrasion can occur between adjacent line wraps as the wraps slip relative to the drum and to one another, thereby reducing the service life of the line. The problem of line abrasion can be particularly acute where the lines employed are constructed of synthetic fibers, such as polyester or nylon, or where the lines are equipped with an external sheath, such as is common in modern marine cordage. Indeed, in yacht racing where trimming of sails is a nearly continuous requirement and line loads tend to be maximized, there are many known occasions wherein line abrasion due to winch operations has required line replacement after each race.
The foregoing problems have been previously recognized and addressed by the prior art with only modest success. For instance, sailing winch drums have been produced whose spool portions are provided with a plurality of spaced apart relatively deep flutes coaligned with the longitudinal axis of the drum. Also, marine winch drum spools having a rough surface texture, such as producible by abrasive blasting or etching of the spool surface, are known. Indeed, even coating of a drum spool with a coarse ceramic material has been attempted. None of these techniques, however, provides a permanent solution to these problems. The fluting technique mentioned tends to yield too much of an increase in line holding power and has little effect on the problem of wrap to wrap chafing of the line. Providing the drum spool with a rough surface texture or coating the spool with a coarse ceramic tends to provide only temporary improvements in drum performance because, during the course of use of the winch, these approaches tend to wear away or spall from the spool surface. In accordance with the present invention, however, the foregoing problems have been successfully addressed.